The present invention relates to a method of failover in redundant systems, and more particularly, to a method for maintaining a sequence of events function during a failover in a redundant system having multiple layers.
In a process control system, the system of the preferred embodiment, intermediate layers (of a hierarchical scheme of the system) between an input device and a historization device have redundancy due to process control security needs. As a result, the sequence of events information could be lost in the event of a failover. Thus, there is provided by the present invention a method which maintains the sequence of events information from multiple modes of a network even if one or more of these nodes should sustain a failover.